Charmonium-hadron interactions from QCD

The heavy quark system is an excellent probe to learn about the QCD dynamics at finite density. First, we discuss the properties of the $J/\psi$ and $D$ meson at finite nucleon density. We discuss why their properties should change at finite density and then introduce an exact QCD relation among these hadron properties and the energy momentum tensor of the medium. Second, we discuss attempts to calculate charmonium-hadron total cross section using effective hadronic models and perturbative QCD. We emphasize a recent calculation, where the cross section is derived using QCD factorization theorem. We conclude by discussing some challenges for SIS 200.Comment: 8 pages, Presented at 6th International Conference on Strange Quarks in Matter: 2001: A Flavorspace Odyssey (SQM2001), Frankfurt, Germany, 25-29 Sep 2001, submitted to J. Phys.

Charmonium-Nucleon Dissociation Cross Sections in the Quark Model

Charmonium dissociation cross sections due to flavor-exchange charmonium-baryon scattering are computed in the constituent quark model. We present results for inelastic $J/\psi N$ and $\eta_c N$ scattering amplitudes and cross sections into 46 final channels, including final states composed of various combinations of $D$, $D^*$, $\Sigma_c$, and $\Lambda_c$. These results are relevant to experimental searches for the deconfined phase of quark matter, and may be useful in identifying the contribution of initial $c\bar c$ production to the open-charm final states observed at RHIC through the characteristic flavor ratios of certain channels. These results are also of interest to possible charmonium-nucleon bound states.Comment: 10 pages, 5 eps figures, revte

Molecular beam epitaxial growth of high-quality InSb on InP and GaAs substrates

Epitaxial layers of InSb were grown on InP and GaAs substrates by molecular beam epitaxy. The dependence of the epilayer quality on flux ratio, J sub Sb4/J sub In, was studied. Deviation from an optimum value of J sub Sb4/J sub In (approx. 2) during growth led to deterioration in the surface morphology and the electrical and crystalline qualities of the films. Room temperature electron mobilities as high as 70,000 and 53,000 sq cm /V-s were measured in InSb layers grown on InP and GaAs substrates, respectively. Unlike the previous results, the conductivity in these films is n-type even at T = 13 K, and no degradation of the electron mobility due to the high density of dislocations was observed. The measured electron mobilities (and carrier concentrations) at 77 K in InSb layers grown on InP and GaAs substrates are 110,000 sq cm/V-s (3 x 10(15) cm(-3)) and 55,000 sq cm/V-s (4.95 x 10(15) cm(-3)), respectively, suggesting their application to electronic devices at cryogenic temperatures